JP4110947B2 - Pressure spray oil burner - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a burner structure with improved combustion characteristics of a pressure spray type oil combustor.
[0002]
[Prior art]
A bottomed cylindrical combustion cylinder is arranged in a blower cylinder to which combustion air is sent by a combustion fan, and an opening is provided in the center of the bottom plate of the combustion cylinder so as to be covered with a fuel spray nozzle. A swirl vane is arranged around the.
[0003]
On the other hand, the fuel spray nozzle is attached to the discharge side of the fuel pump. When the fuel pump is operated, the pressurized fuel is sprayed in a mist form from the outlet of the fuel spray nozzle. Is sent into the combustion cylinder. In addition, a pair of ignition electrodes are attached between the opening at the center of the bottom plate and the fuel spray nozzle to generate discharge sparks, and the mist fuel is ignited by the sparks flying between the tips of the ignition electrodes.
[0004]
When the mist fuel sent forward from the opening at the center of the bottom plate with the swirl vane is ignited and combustion starts, a part of the mist fuel in the middle of combustion diffuses as a combustible gas in front of the swirl vane When combustion air is supplied from the swirl vane by the combustion fan, the flame adheres to the swirl vane to form a ring-shaped fire, and the atomized fuel ejected from the fuel spray nozzle stops the discharge of the ignition electrode. However, the combustion can continue without extinguishing the fire.
[0005]
Many air holes are provided on the side wall of the combustion cylinder, and the air flowing between the blower cylinder and the combustion cylinder is supplied from the air holes toward the side of the combustion flame, thereby promoting combustion in the combustion cylinder. It is what
[0006]
By the way, in the case of a pressure spray type oil combustor with variable combustion capacity, when the state of the combustion flame changes depending on the discharge pressure from the fuel spray nozzle, the front and rear parts in the combustion cylinder are adjusted according to the spread of the spray and the combustion speed. Some have different diameters, and the diameter of the front cylinder is larger than the diameter of the rear cylinder.
[0007]
[Problems to be solved by the invention]
In the case of such a structure, the larger the combustion capacity, the more the combustion cylinder is combusted and the combustion is completed near the front cylinder where the diameter of the combustion cylinder is large, but the smaller the combustion capacity, the smaller the diameter of the combustion cylinder. Combustion is completed near the rear cylinder. When the combustion capacity is reduced and the air shortage combustion occurs due to a disturbance factor or the like, the combustion is not completed in the rear cylinder, and the combustion flame extends to the front cylinder and is supplied from the side wall air hole of the front cylinder. The combustion air contributes to the combustion flame while attracting the combustion flame that has become the air shortage combustion to the front cylinder side wall, but the combustion flame lowers the flame temperature by this air flow. Ingredients that hardly volatilize, tar content will accumulate.
[0008]
[Means for Solving the Problems]
The present invention solves the above-described problem. A combustion cylinder 3 having a bottomed cylindrical shape and provided with air holes 3c in a side wall is disposed in a blower cylinder 2 to which combustion air is sent by a combustion fan 1, and the combustion cylinder 3 is The diameter of the front cylinder 3a on the tip end side of the blower cylinder 2 is increased, the diameter of the rear cylinder 3b near the bottom plate 4 of the combustion cylinder 3 is set small , and the front cylinder 3a and the rear cylinder 3b having different diameters are interposed between them. A ring-shaped step portion 6 is disposed , and an opening 4a is provided at the center of the bottom plate 4 of the combustion cylinder 3 so as to be seen by the combustion spray nozzle 5. The bottom plate 4 of the combustion cylinder 3 around the opening 4a is swiveled. In the oil combustor provided with the blades 4b, the air holes 3c on the side wall of the combustion cylinder 3 are provided only on the side wall of the rear cylinder 3b, and the forward air holes 6a are arranged in the ring-shaped step portion 6 of the combustion cylinder 3 , And between the front-end | tip part of the ventilation cylinder 2 and the front edge of the front part cylinder 3a, it is air ahead of the combustion cylinder 3. A slit-shaped air supply passage 7 for feeding, said spray nozzle 5 is connected to the fuel pump 9 equipped with a discharge pressure changing means 8, the combustion flame of the combustion amount is suppressed by the discharge pressure changing means 8 This is a pressure spray type oil combustor with variable combustion capability, characterized in that forward combustion air is supplied from the forward air hole 6a and burned in the center of the combustion cylinder 3 .
[0009]
Further, a ring-shaped front plate 2a facing inward is provided at the front edge of the blow tube 2, and an outer flange 3d toward the back surface of the front plate 2a is formed at the front edge of the combustion tube 3, The flange 3d is provided with a plurality of protrusions 3e protruding to the front surface side, and the air supply path 7 is formed by a gap between the front plate 2a and the outer flange 3d generated when the protrusion 3e contacts the inner wall of the front plate 2a. With the formed structure, the gap between the front plate 2a and the outer flange 3d was formed uniformly, and the combustion air blowing pressure applied to the combustion cylinder 3 could be made uniform over the entire circumference.
[0010]
Further, the ring-shaped front plate 2a provided at the front edge of the blow tube 2 is formed in a taper shape facing diagonally forward, so that the combustion air supplied through the air supply path 7 is a combustion gas or a combustion flame. It came to be supplied smoothly without disturbing.
[0011]
[Action]
In the present invention, since the forward air hole 6a is provided in the step portion 6 between the front cylinder 3a and the rear cylinder 3b, and no air hole 3c is provided in the front cylinder 3a, the fuel having the discharge pressure varying means 8 is provided. Even when the combustion capacity is reduced by the pump 9, even when air shortage combustion occurs due to a disturbance factor or the like, the combustion air is supplied from the forward air hole 6a without drawing the combustion flame to the side wall of the front cylinder 3a. The combustion flame which became the air short combustion extending to the front cylinder 3a is mixed with the forward combustion air from the forward air hole 6a while moving forward, and combustion is promoted near the center of the combustion cylinder 3. .
[0012]
【Example】
This configuration will be described with reference to FIG. 1 showing an embodiment. 2 is a blower cylinder to which combustion air is sent, 3 is a bottomed cylindrical combustion cylinder disposed in the blower cylinder 2, and 3 a is a blower of the combustion cylinder 3. A front cylinder 3b having a large diameter disposed on the front end side of the cylinder 2 is a rear cylinder 3b having a small diameter disposed on one of the front cylinders 3a among the combustion cylinders 3 and can supply combustion air from the blow cylinder 2 Thus, a number of air holes provided in the side wall of the combustion cylinder 3, 4 is a bottom plate which is the bottom surface of the bottomed cylindrical combustion cylinder 3, 4 a is an opening in the center of the bottom plate, 4 b is a swirl vane provided around the opening 4 a is there.
[0013]
Reference numeral 1 denotes a combustion fan for supplying combustion air into the combustion cylinder 3 through the blower cylinder 2, and since the combustion fan 1 has been rotating since the start of operation, the combustion air has an opening 4a and swirl vanes 4b. And the air hole 3c on the side wall of the combustion cylinder 3 are fed into the combustion cylinder 3, and are appropriately controlled by the position and size of the air hole 3c and supplied into the combustion cylinder 3.
[0014]
Reference numeral 5 denotes a fuel spray nozzle inserted into the opening 4a in the center of the bottom plate 4 of the combustion cylinder 3. Reference numeral 9 denotes a fuel pump connected to the fuel spray nozzle 5. When the fuel pump 9 is operated, fuel is discharged from the fuel pump 9. Pressurized according to the capacity and sent to the fuel spray nozzle 5 to be sprayed into the combustion cylinder 3 from the opening 4a as mist fuel.
[0015]
Reference numeral 10 denotes a discharge ignition device whose tip is positioned between the fuel spray nozzle 5 and the opening 4a of the combustion cylinder 3. In this type of pressure spray type oil combustor, when an operation switch (not shown) is operated, a combustion fan 1 starts rotating, and then the discharge ignition device 10 is operated to generate a discharge spark from the tip electrode. After that, when the fuel pump 9 is operated, mist fuel is ejected from the fuel spray nozzle 5. The fuel is ignited by the discharge spark, and the flame is blown into the combustion cylinder 3.
[0016]
On the other hand, the air sent from the swirl vane 4 b is blown in an oblique direction by the swirl vane 4 b to form an air flow that rotates in the combustion cylinder 3. A part of the ignited mist fuel blown into the combustion cylinder 3 from the opening 4a is vaporized by combustion heat, combusted and diffused in front of the swirl vane 4b, and this combustible gas is swirled by the swirl vane 4b. It is burned by the air blown out from the gap, forming a ring-shaped flame attached to the swirl vane 4b. For this reason, even if the discharge ignition device 10 is stopped after the ignition is confirmed, the combustion flame can be maintained without interruption by the ring-shaped fire on the front surface of the swirl vane 4b.
[0017]
The combustion flame in the combustion cylinder 3 is blown forward while being directed by the air flow blown from the swirl vane 4b to create a rotating flow, and is formed from the air hole 3c on the side wall of the combustion cylinder 3 to the side of the combustion flame. Since the air is supplied to the combustion flame, the combustion flame promotes the combustion forward while rotating in a spiral shape in the combustion cylinder 3.
[0018]
8 is a discharge pressure variable means for varying the flow rate of the fuel ejected from the fuel spray nozzle 5 by the fuel pump 9, and the discharge flow rate of the fuel pump 9 is increased by the discharge pressure variable means 8, and the front portion is increased as the combustion capacity increases. Combustion is performed in the entire combustion cylinder 3 of the cylinder 3a and the rear cylinder 3b, and the combustion is completed in the vicinity of the front cylinder 3a having a large diameter. Further, the combustion is completed near the rear cylinder 3b having a smaller diameter as the combustion capacity is reduced by reducing the discharge flow rate of the fuel pump 9, that is, the combustion air supplied from the side wall air hole 3c of the front cylinder 3a having a larger diameter is By preventing most from contributing to combustion, even a pressure spray type oil combustor can perform combustion with variable combustion amount.
[0019]
In FIG. 2 showing an embodiment of the discharge pressure variable means 8, 8 a is a discharge amount variable pump connected to the suction side of the fuel pump 9 for generating spray pressure, and 8 b is a fuel spray nozzle 5 and the suction side of the fuel pump 9. A return pipe to be connected, 8c is a solenoid valve attached to the return pipe 8b, 8d is a check valve attached to the return pipe 8b to allow flow to the suction side of the fuel pump 9, and the variable discharge amount pump 8 is a fuel spray. The fuel flow rate ejected from the nozzle 5 is controlled, and the fuel pump 9 increases the fuel pressure so that the sprayed flow rate can be normally obtained at least from the fuel spray nozzle 5.
[0020]
Since the fuel pump 9 needs a constant flow rate to create a pressure suitable for spraying, even when the flow rate is suppressed by the discharge amount variable pump 8a, fuel is returned from the return pipe 8b via the check valve 8d. By returning to the suction side, the flow rate passing through the fuel pump 9 can be secured to increase the pressure, and the fuel flow rate controlled by the discharge amount variable pump 8a can be sprayed from the fuel spray nozzle 5.
[0021]
Another embodiment of the discharge pressure varying means 8 can be realized by a drive control device for the fuel pump 9 such as a microcomputer. In general, since the control device for the fuel pump 9 that changes the discharge flow rate only changes the drive frequency, the discharge pressure cannot be made high enough to be suitable for spraying. However, as shown in FIG. The spray flow rate can be changed by changing the energization width of the pump 9.
[0022]
That is, by setting the frequency at which the fuel pump 9 is driven and the energization width at that time, it is possible to obtain a spray state when the combustion capacity is small, and by increasing the energization width, the fuel flow rate to be sprayed is increased. In addition, since the spraying pressure can be optimized by increasing the driving frequency, the discharge pressure varying means 8 can be realized by a pump control device using a microcomputer.
[0023]
When the discharge pressure varying means 8 has a small combustion capacity with a narrow energization width and a reduced pulse drive frequency, the fuel spray nozzle 5 is in close contact with the spray limit pressure. The spray particle size of the atomized fuel ejected from the nozzle is large, the vaporization speed of the atomized fuel is slow, the combustion flame reaches the front cylinder 3a, and the combustion heat is used for vaporizing the atomized fuel, and the flame temperature is lowered. And more susceptible to air shortages.
[0024]
When the combustion capacity is reduced by the discharge pressure variable means 8 and the combustion flame is completed in the vicinity of the rear cylinder 3b, when the air shortage combustion occurs due to a disturbance factor or the like, the combustion is not completed in the rear cylinder 3b having a small diameter. The combustion flame extends to the front cylinder 3a having a large diameter. At this time, the combustion air supplied from the air hole in the side wall of the front cylinder 3a is supplied to the combustion flame. Since the combustion is performed in the vicinity of the air hole, the flame temperature is lowered by being cooled by the low temperature front cylinder 3a, and a tar component which is a component that hardly volatilizes in the fuel is easily deposited on the side wall of the front cylinder 3a. .
[0025]
Moreover, once the tar content is accumulated on the side wall of the front cylinder 3a, the unburned fuel is absorbed in the mist fuel ejected from the fuel spray nozzle 5 at the time of ignition and extinguishing, and is tarized without being vaporized. This is a vicious cycle in which the tar content accumulates steadily. Finally, the air hole 3c supplying the combustion air is blocked, and the accumulated tar content is peeled off and fine soot is discharged, and the surroundings are soiled with soot. There is a fear.
[0026]
The present invention solves the above-mentioned problems, 6 is a combustion cylinder 3, a ring-shaped step between the front cylinder 3a and the rear cylinder 3b having different diameters, and 6a is disposed forward in the step 6. It is a forward air hole, and the air hole 3c on the side wall of the combustion cylinder 3 is provided only on the side wall of the rear cylinder 3b having a small diameter, that is, no air hole 3c is provided on the side wall of the front cylinder 3a having a large diameter. This is the structure of the combustion cylinder 3.
[0027]
In the combustion in which the amount of combustion is suppressed by the discharge pressure variable means 8, according to the above structure, even when the combustion flame with air shortage extends to the front cylinder 3a having a large diameter, a large number provided in the front cylinder 3a. In place of the air holes, combustion air can be supplied from a plurality of forward air holes 6a arranged in the ring-shaped step 6 between the front cylinder 3a and the rear cylinder 3b, up to the front cylinder 3a. The combustion flame that has become the extended air shortage combustion is mixed with the forward combustion air from the forward air hole 6a while facing forward, and the combustion is promoted near the center of the combustion cylinder 3, so even when the air shortage combustion occurs The entire combustion cylinder 3 can be used to approach complete combustion, and tar can be eliminated from the inner surface of the combustion cylinder 3.
[0028]
In this way, the accumulation of tar content is eliminated, so that the unburned mist fuel ejected from the fuel spray nozzle 5 at the time of ignition and extinguishing is not absorbed by the tar content and used for a long time. A vicious cycle of tar accumulation due to repeated ignition and extinction was prevented. Moreover, there is no adverse effect on the combustion state due to the accumulation of the tar content, and it is possible to provide a pressure spray type oil combustor that does not pollute the surroundings by peeling off the accumulated tar content.
[0029]
By the way, in the state where the discharge pressure variable means 8 is set to a large combustion capacity, it should be able to complete combustion with the air supplied from the air hole 3c of the combustion cylinder 3, but as with the case where the combustion capacity is set small, Air-deficient combustion may occur due to disturbance factors. Reference numeral 7 denotes an air supply path formed between the front end of the blow cylinder 2 and the front edge of the front cylinder 3a. This air supply is applied to the combustion flame extending forward of the combustion cylinder 3 with the air shortage combustion. By supplying the air in the blower cylinder 2 from the passage 7, air shortage combustion is eliminated and complete combustion occurs, so that it is possible to prevent soot from being mixed in the combustion exhaust gas.
[0030]
However, when the structure in which the forward air hole 6a is provided in the step portion 6 and the air hole is eliminated in the side wall of the front tube 3a and the structure in which the air supply path 7 is provided are combined, the air hole of the rear tube 3b is formed by the step portion 6. Both 3c and the forward air hole 6a of the stepped portion 6 are easily affected by the flow of air toward the tip of the blow tube 2. If this air supply path 7 is not formed uniformly, a relatively large amount of combustion air is supplied to the front of the combustion cylinder 3 from a location where the gap is partially large in the air supply path 7. For this reason, there exists a part where the blowing pressure of the combustion air supplied from the air hole 3c on the side wall of the combustion cylinder 3 is partially weakened, and the weakened part of the combustion flame is partly air short-burned and burned. When the capacity is reduced, there is a problem that the combustion flame partially extends to the front cylinder 3a.
[0031]
As for the combustion flame partially extending to the front cylinder 3a in this way, it is difficult to supplement the combustion only with the combustion air supplied in the combustion cylinder 3, and the combustion flame extending due to air shortage combustion due to disturbance factors or the like is It reached the heat exchanger in front of the combustion cylinder 3 and caused troubles such as generation of resonance noise and combustion smoke.
[0032]
In another embodiment of the present invention shown in FIG. 4, 2 a is a ring-shaped front plate facing inward to the front edge of the blower cylinder 2, and 3 d is on the back surface of the front plate 2 a provided at the front edge of the combustion cylinder 3. Outward flanges 3e are a plurality of projections projecting from the front side of the outer flange 3d toward the ring-shaped front plate 2a, and the air supply path 7 is generated when the projections 3e abut against the inner wall of the front plate 2a. The gap between the front plate 2a and the outer flange 3d is uniformly formed over the entire circumference.
[0033]
Since the air supply path 7 is formed uniformly over the entire circumference in this way, the amount of passing air does not fluctuate partially even if a slight error occurs in the attachment between the combustion cylinder 3 and the blower cylinder 2, and the rear cylinder The blowing pressure for supplying combustion air into the combustion cylinder 3 from the air hole 3c on the side wall 3b and the forward air hole 6a of the step portion 6 is stabilized, and the combustion air is uniformly supplied over the entire circumference. It was possible to prevent partial combustion flame growth due to air shortage combustion.
[0034]
In another embodiment of the present invention shown in FIG. 5, the distance between the outer flange 3d at the front edge of the combustion cylinder 3 and the front plate 2a at the front edge of the blower cylinder 2 is maintained uniformly by the projection 3e. The front plate 2a is formed in a tapered shape so as to face obliquely forward.
[0035]
By adopting such a shape of the front plate 2a, the combustion air supplied through the air supply path 7 is blown obliquely forward along the front plate 2a, so that the combustion air supplied from the air supply path 7 is combusted. The combustion gas supplied from the air supply path 7 does not interfere with the flow of the combustion gas and the combustion flame as in the case of being blown at a right angle from the side with respect to the flow of the flame. In addition, the fuel can be sent smoothly without disturbing the combustion flame, making it easy for the sprayed fuel to burn completely, improving the ignition performance without causing an ignition delay, and reducing the combustion noise.
[0036]
【The invention's effect】
As described above, in the present invention, the combustion cylinder 3 arranged inside the blower cylinder 2 is constituted by the front cylinder 3a and the rear cylinder 3b having different diameters, and the air holes 3c of the combustion cylinder 3 are opened only in the rear cylinder 3b. In addition, since the forward air hole 6a is disposed in the step portion 6 between the front cylinder 3a and the rear cylinder 3b, air shortage combustion is caused by a disturbance factor or the like in a state where the combustion amount is suppressed by the discharge pressure variable means 8. Even if it occurred, it was possible to approach the complete combustion using the entire combustion cylinder 3. In addition, since no soot or tar accumulates on the side wall of the front cylinder 3a, a pressure spray type oil combustor is provided that does not pollute the surroundings by peeling off the tar accumulated in the combustion cylinder 3 as in the past. I was able to do that.
[0037]
Further, a ring-shaped front plate 2a is formed at the front edge of the blower cylinder 2, and an outer flange 3d is formed at the front edge of the combustion cylinder 3 toward the back surface of the front plate 2a. The outer flange 3d faces the front plate 2a. The projection 3e is formed, and a uniform gap is formed between the front plate 2a and the outer flange 3d to form the air supply path 7, so that the blowing pressure in the blowing cylinder 2 becomes uniform over the entire circumference and the air is insufficient. Partial elongation of the combustion flame due to combustion could be prevented. Further, even when air shortage combustion occurs due to disturbance factors or the like, a stable combustion state can be maintained.
[0038]
Further, when the front plate 2a formed at the front edge of the blower cylinder 2 is formed in a tapered shape, the combustion air supplied to the front of the combustion cylinder 3 through the air supply path 7 is obliquely forward along the front plate 2a. It came to be blown out. For this reason, the partial combustion flame does not extend due to the partial air shortage combustion, and the combustion air from the air supply path 7 is smoothly supplied without disturbing the combustion gas and the combustion flame, and the ignition is performed. A pressure spray type oil combustor with improved performance and reduced combustion noise can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part of a pressure spray type oil combustor showing an embodiment of the present invention.
FIG. 2 is an explanatory view showing an embodiment of a discharge pressure varying means.
FIG. 3 is an explanatory view showing an operation state in another embodiment of the discharge pressure varying means.
FIG. 4 is a cross-sectional view of an essential part of a pressure spray type oil combustor showing another embodiment of the present invention.
FIG. 5 is a cross-sectional view of an essential part of a pressure spray type oil combustor showing another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Combustion fan 2 Blower cylinder 2a Front plate 3 Combustion cylinder 3a Front cylinder 3b Rear cylinder 3c Air hole 3d Outer flange 3e Projection 4 Bottom plate 4a Opening 4b Swirling blade 5 Fuel spray nozzle 6 Step part 6a Forward air hole 7 Air supply path 8 Discharge pressure variable means 9 Fuel pump

Claims (3)

A combustion cylinder 3 having a bottomed cylindrical shape and provided with air holes 3c in a side wall is arranged in a blower cylinder 2 to which combustion air is sent by a combustion fan 1,
The combustion cylinder 3 has a large diameter of the front cylinder 3a on the tip end side of the blower cylinder 2 and a small diameter of the rear cylinder 3b in the vicinity of the bottom plate 4 of the combustion cylinder 3, and the front cylinder 3a and the rear cylinder having different diameters. While arrange | positioning the ring-shaped step part 6 between 3b ,
An oil combustor provided with an opening 4a in the center of the bottom plate 4 of the combustion cylinder 3 and a swirl vane 4b provided on the bottom plate 4 of the combustion cylinder 3 around the opening 4a.
The air hole 3c on the side wall of the combustion cylinder 3 is provided only on the side wall of the rear cylinder 3b, and the forward air hole 6a is disposed in the ring-shaped step portion 6 of the combustion cylinder 3 ,
In addition, a slit-shaped air supply path 7 for supplying air to the front of the combustion cylinder 3 is formed between the front end of the blow cylinder 2 and the front edge of the front cylinder 3a.
A fuel pump 9 having a discharge pressure variable means 8 is connected to the spray nozzle 5 ,
Pressure spraying type oil with variable combustion capacity, characterized in that forward combustion air is supplied from a forward air hole 6a to a combustion flame whose combustion amount is suppressed by the discharge pressure variable means 8 and burned at the center of the combustion cylinder 3. Combustor. A ring-shaped front plate 2a facing inward is provided on the front edge of the blow tube 2,
And the outer flange 3d which goes to the back surface of the front board 2a is formed in the front edge of the combustion cylinder 3,
The outer flange 3d is provided with a plurality of protrusions 3e protruding to the front side,
2. The pressure spray type oil combustor according to claim 1, wherein the air supply path is formed by a gap between the front plate 2 a and the outer flange 3 d generated by the protrusion 3 e coming into contact with the inner wall of the front plate 2 a.   The pressure spray type oil combustor according to claim 2, wherein a ring-shaped front plate 2 a provided at a front edge of the blower cylinder 2 is formed in a tapered shape facing obliquely forward.

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